Goggles which are intended for use in an outdoor or other adverse environment include sports goggles such as for skiing or motorcycle use, as well as safety goggles. Such goggles provide protection for the wearer's eyes from external air and particulate matter. The goggles may have vent apertures open to external air flow to exchange air between the exterior environment and the interior of the goggle. Such a vented exchange of air will minimize fogging caused by moisture in the air condensing on the lens of the goggle. The vent apertures are typically covered by a porous foam to control the air exchange while forming a partial barrier to snow, dust and other particulate matter. The goggles also include replaceable plastic lenses which may be a single lens or a double lens, and such lenses can be tinted in various colors to assist in contrast and glare protection.
While certain improved contrast resolution capabilities have been available in fixed glass lenses for eyeglasses and sunglasses, there is a need for improved contrast resolution capabilities which are specifically adapted to plastic lenses for goggle use. In the case of a sports goggle or safety goggle, for example, there is a need for a plastic lens which is lighter and more shatter-resistant than glass but which has improved contrast resolution over a wide variety of light conditions. In particular, it is desirable to provide a plastic lens for a goggle which has improved contrast resolution in low light conditions in which it is difficult to distinguish between adjacent surface areas which are partially in shadow conditions. Such adverse conditions in a sports goggle such as a ski goggle can result from snow and fog which create whiteout conditions, whereas such conditions in a safety goggle can result from heavy particulate matter in the air.
High contrast resolution is desirable in plastic spherical lens of variable thickness such as formed by injection molding of polycarbonate material. In addition, the availability of high contrast resolution is desirable for a thermoplastic lens stamped from flat sheets of extruded resin, such as cellulosics, which form a cylindrical goggle lens. Furthermore, such thermoplastic lenses desirably are removably mounted such as in a peripheral groove of a flexible injection molded plastic frame for a sports goggle or a safety goggle. Furthermore, there is a need in a goggle to better coordinate the plastic lens materials, dyes and coatings with venting capabilities of a vented goggle to improve the overall anti-fogging and vision properties of the goggle.